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authorLi Xinhai <lixinhai.lxh@gmail.com>2020-01-30 22:13:45 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2020-01-31 10:30:38 -0800
commit5b8d6e37b519e455661cd847654c2e6ad20b4b1d (patch)
treefcbc36d500bc0bb9c75849cc091472362731c67b /mm
parent92855270ff0827865109447b59e7e5df9c2bef68 (diff)
mm/page_vma_mapped.c: explicitly compare pfn for normal, hugetlbfs and THP page
When check_pte, pfn of normal, hugetlbfs and THP page need be compared. The current implementation apply comparison as - normal 4K page: page_pfn <= pfn < page_pfn + 1 - hugetlbfs page: page_pfn <= pfn < page_pfn + HPAGE_PMD_NR - THP page: page_pfn <= pfn < page_pfn + HPAGE_PMD_NR in pfn_in_hpage. For hugetlbfs page, it should be page_pfn == pfn Now, change pfn_in_hpage to pfn_is_match to highlight that comparison is not only for THP and explicitly compare for these cases. No impact upon current behavior, just make the code clear. I think it is important to make the code clear - comparing hugetlbfs page in range page_pfn <= pfn < page_pfn + HPAGE_PMD_NR is confusing. Link: http://lkml.kernel.org/r/1578737885-8890-1-git-send-email-lixinhai.lxh@gmail.com Signed-off-by: Li Xinhai <lixinhai.lxh@gmail.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/page_vma_mapped.c12
1 files changed, 8 insertions, 4 deletions
diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c
index eff4b4520c8d..719c35246cfa 100644
--- a/mm/page_vma_mapped.c
+++ b/mm/page_vma_mapped.c
@@ -52,12 +52,16 @@ static bool map_pte(struct page_vma_mapped_walk *pvmw)
return true;
}
-static inline bool pfn_in_hpage(struct page *hpage, unsigned long pfn)
+static inline bool pfn_is_match(struct page *page, unsigned long pfn)
{
- unsigned long hpage_pfn = page_to_pfn(hpage);
+ unsigned long page_pfn = page_to_pfn(page);
+
+ /* normal page and hugetlbfs page */
+ if (!PageTransCompound(page) || PageHuge(page))
+ return page_pfn == pfn;
/* THP can be referenced by any subpage */
- return pfn >= hpage_pfn && pfn - hpage_pfn < hpage_nr_pages(hpage);
+ return pfn >= page_pfn && pfn - page_pfn < hpage_nr_pages(page);
}
/**
@@ -108,7 +112,7 @@ static bool check_pte(struct page_vma_mapped_walk *pvmw)
pfn = pte_pfn(*pvmw->pte);
}
- return pfn_in_hpage(pvmw->page, pfn);
+ return pfn_is_match(pvmw->page, pfn);
}
/**